To achieve its goals, DT-GEO will build the components of a Digital Twin- virtual replica of physical systems that combine real-time data streams and high-fidelity models. Digital twins are built on interactive digital platforms, which allow for continuous observation and simulation of supercomputing tasks to recreate present and future scenarios. DT-GEO capitalises on the outburst of supercomputing and technical capabilities to carry out advanced, real-time modelling and analysis for diagnostics and forecasting.